linux-kernel - RE: [PATCH 1/3] block: Requeue req as head if driver touched it

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <4e2b1f4c81ca478cb7e5644f5ae892cb@hyperstone.com>
Date:   Wed, 18 Jan 2023 13:08:06 +0000
From:   Christian Löhle <CLoehle@...erstone.com>
To:     "axboe@...nel.dk" <axboe@...nel.dk>,
        "ulf.hansson@...aro.org" <ulf.hansson@...aro.org>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-block@...r.kernel.org" <linux-block@...r.kernel.org>
CC:     Avri Altman <Avri.Altman@....com>,
        "adrian.hunter@...el.com" <adrian.hunter@...el.com>,
        "vincent.whitchurch@...s.com" <vincent.whitchurch@...s.com>,
        "bvanassche@....org" <bvanassche@....org>
Subject: RE: [PATCH 1/3] block: Requeue req as head if driver touched it

Jens could you consider this patch?
As far as I can see Barts series has not been merged in any form that would fix my problem and even if it does, requeuing RQF_DONTPREP as head seems on par at worst and a performance improvement at best.


-----Original Message-----
From: Christian Löhle 
Sent: Mittwoch, 26. Oktober 2022 09:29
To: axboe@...nel.dk; ulf.hansson@...aro.org; linux-mmc@...r.kernel.org; linux-kernel@...r.kernel.org; 'linux-block@...r.kernel.org' <linux-block@...r.kernel.org>
Cc: 'Avri Altman' <Avri.Altman@....com>; adrian.hunter@...el.com; vincent.whitchurch@...s.com; 'Christian Löhle' <CLoehle@...erstone.com>
Subject: [PATCH 1/3] block: Requeue req as head if driver touched it

In case the driver set RQF_DONTPREP flag, requeue the request as head as it is likely that the backing storage already had a request to an adjacent region, so getting the requeued request out as soon as possible may give us some performance benefit.

Signed-off-by: Christian Loehle <cloehle@...erstone.com>
---
 block/blk-mq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c index 33292c01875d..d863c826fb23 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1429,7 +1429,7 @@ static void blk_mq_requeue_work(struct work_struct *work)
 		 * merge.
 		 */
 		if (rq->rq_flags & RQF_DONTPREP)
-			blk_mq_request_bypass_insert(rq, false, false);
+			blk_mq_request_bypass_insert(rq, true, false);
 		else
 			blk_mq_sched_insert_request(rq, true, false, false);
 	}
--
2.37.3

Hyperstone GmbH | Reichenaustr. 39a  | 78467 Konstanz
Managing Director: Dr. Jan Peter Berns.
Commercial register of local courts: Freiburg HRB381782